Ate a level 10 Legacy Champion, three times.
Doesn't work the way you hope.
Ha, I was actually going to suggest that a few posts back when I made comments on the gloura, but the "I am attempting to keep it reasonable" kept me from doing so. Although I am not sure what PlzBreakMyCampaign thinks does not work? Now you cannot over progress the savant past 10 levels (need the seperate epic savant class, then you are in business), but there is nothing stopping you from dipping a level in a few different classes and then progressing them by 8 levels per Legacy champion. Such as:
Psionic Mindflayer 15/Thrallherd 1/Illthiad savant 3
Eat twice for 16 levels of class ability progression to pick up 7 levels of savant and 9 levels of Thrallherd. The thrallherd can progress the telepath 9 the psionic mindflayer has to net you 17th level psions. You new thralls will also help you pick up other abilities as needed later. Add classes as needed with more class ability progression.
Psionic Mindflayer 15/Factotum 1/ Illithiad savant 3/ Factotum 1 with three eats gets you savant 10 and factotum 19.
If you have trouble finding a second Legacy Champion, remeber you can also resurrect the first after you munch on his brians.
What happens when an I.S. eats an Artificer brain ??
Really. I have no idea ?!
Might be better off eating a midguard dwarf from Frostburn if you want to craft. Not sure the Infusions are worth it, although there are few of note.