You don't ACTUALLY need to pay for labor to get things built. Really.
First, let me point you to the 'stuff creation' / stuff changing spells. You already have the plant is permanent Major Creation; kudos for not needing a Simulacrum of a Djinn to do it! You probably know most of these, but here is all of them that I can find
Wall of Iron
Wall of Stone
Greater Stone Metamorphosis
Ironwood
Transmute Rock to Mud
Transmute Mud to Rock
Transmute Metal to Wood
Transmute Stone to Sand
Transmute Sand to Glass
Soften Earth and Stone
Invisible Spell (the feat, on a rod, make invisible whatever)
Look at these labor-doing-for-free spells:
Move Earth
Unseen Servant
Unseen Crafter (This is a BIG ONE)
Shape Metal
Metal Melt (use for welding by melting small items on two big ones)
Stone Shape
Fabricate (This is a BIG ONE)
Greater Stone Shape
Nature's Rampart
Magecraft
Planar Ally
Planar Binding
Lyre of Building (an item not a spell, of course. And remember you can take 10!)
Remember, SBG is NOT the end all of prices on stuff! For example, there are DMG prices too:
http://www.d20srd.org/srd/wilderness.htm#cityBuildingsAnd Cityscape has prices as well (villa/manor costs 2d8*1000gp)
Also figure out WHICH of these methods the DM likes for making emplacements (like that can go on a ship or sit in the middle of town) that auto cast a spell:
1.) Eternal Wands, from Magic Item Compendium. They have a little bit of an extra surcharge on them from the DMG formula, but gives 2/day casting of spells levels 1-3.
2.) Magical traps using the DMG rules for recharge and stuff. Note that if you want precedent for magical traps that are beneficial, look at the Boon traps in Dungeonscape
3.) Drow House Insignia sorts of items, explained in the book Races of Faerun, pg 175. Basically use the DMG rules, but this gives a specific form, 1/day limitation, and certain spell levels, I think 1-3.
4.) Minor Schema, from the book Magic of Eberron (A way to cast spells lvl 1-6, once a day, I believe)
5.) Generic wondrous items that cast spells, per the DMG rules for custom magic items
6.) Spell Turrets, from Dungeon Master's Guide II
7.) Spell clocks, from here:
http://www.wizards.com/default.asp?x=dnd/cw/20070312a&dcmp=ILC-RSSDNDAlso figure out the DM's ruling on combining magic items per DMG, with the weirdness on how the order in which you combnine items makes a difference for some reason (this could matter).
Some of the cheaper ways to get large airships aloft (aside from soarwood) would probably be the Suspension spell from EDIT: SHINING SOUTH. Once you get it aloft with that, it's MUCH cheaper to add mobility via the SBG options. Also you could use a decanter of endless water + riverine container with riverine nozzle + some way of creating an eternal wall of flame in the container to create a massive amount of superheated thrust, which you could put on the end of a rudder.
Also Decanters of Endless Water work GREAT for high powered (like wayyy higher than gravity power) waterwheels -- but the wheel is going to have to be really big, ideally. Or a repeating trap of Blockade with a freaking HUGE 'waterwheel' can do a lot of horsepower (a properly made 60 foot wheel with 3 blockade blocks on it at any one time will have as much power as a V6 at 3000 rpm. If you like I can give you my aim conversation with an engineer about that). But if you have a repeating trap of Unseen Crafter, and you maybe research a custom skill for the same thing but for professions (Unseen Worker, perhaps?), you can basically get your output in 'simple crafting, work, and labor' to be damn near infinite. Build a bunch of tools, build a wall / ditch / major construction in a day, etc. Anything DC 11 or so in profession or craft... and you can take 10 on those, and a LOT of things are low DC. As for you? All the SHORT DURATION skill spells work juuuust fiinnnee with Fabricate.
Also, Major Creation of all plant based materials = infinite money as long as you can export. Remember you can export extremely valuable plant based poisons, including ethical poisons like drow poison (it's anesthetic! honest! see? labeled as anesthetic for surgical use, with warnings and instructions on use!) plant based alchemical goods, all those wooods are crazy valuable (serren! densewood! darkwood! bronzewood! livewood! duskwood!), and you have infinite useful plant based items like lacquer, deisel, rubber, resin, glue, paper, cardboard, cumin, silphium, coffee, saffron, tobacco, pepper, chilies, paprika, cacao, anise, poppy, marijuana, etc. Expect scry and die from pissed off trade barons though.
Also, for training followers? Research a version of Magecraft that is touch based, to put in a repeating trap (there's one in Pathfinder if your DM likes that). Then research a version that works on professions. Bam, as long as they have the tools in hand (to serve as foci for the traps), they can competently do any crafting or profession that day. Plus with the repeating traps of Unseen Crafter (and a researched version, Unseen Worker), anyone can do any amount of boring grunt work too.
Other good spells to put in repeating traps on a big boulevard:
Endure Elements
Prestidigitation
Create Food and Water
Purify Food and Drink
Good Hope
Make Whole
Lesser Restoration
Panacea
Low Light Vision
Superior Darkvision
Mount
Bam, everyone is happy, has as much tasty food as they could ever need, no one needs to sleep ever, no one needs shelter, all their equipment is fixed, they are free from disease, they have as many magical horses to haul them or whatever they want or to do labor as they want, they can see in the dark to work because they don't need to sleep ever. With all the infinite wealth and infinite 'free work', instant utopia.
Craft Spell Turrets & heavily templated Effigies to defend it, or get the druid to summon and release (into the hands of an animal trainer) animal companions for training, and you don't have to worry about defense either.
Create something to rival Sharn!