the more i look, and ya... i know im the only one looking, the more i need an extra third level feat.
little bit of train of thought here...
so i ditch practiced caster, replace it with a limited use +1 or 2 cl feat and maybe be a specialist to get my lvl 1 caster level to 3 so i can take craft wondrous item at level 1. not 100% on the legality or limitations on what i could 'craft' with that setup. seems very much a ymmv (check w/ the dm first).
So, assuming that works, best case. take +CL feat X and Craft Wondrous Item.
inline with the theme / goal of the build craft a ''Wand'' that gives a +X spellcraft or concentration bonus.
skill bonus squared x 100gp cost? +1 x 1 x 100gp x 1.5 non slot affinity and 6xp? (yes aiming for cheap initially its just a prop for now)
human wiz 1 spec / domain wiz (what ever for your +1 cl) Precocious (X), craft wondrous item, + cl feat (flaw)
at level 3 retrain the flaw away (if thats an option) or drop your wiz spec and retrain the flaw feat for practiced caster.
so level three is human wiz 1 / warlock 2, precocious, craft wi, item familiar and possibility practiced caster.
invest spell slot in the familiar, give up your 2nd lvl spell to the wand and gain a cantrip for now.
im not 100% clear on some stuff w. precocious. you have a second level slot. if your int is high, you dont get the bonus spells per day? if your a specialist it doesnt add a school slot for 2nd lvl spells? i see it as 3 slots (2 at least), but i doubt thats correct. seems like a big boon for a simple feat.
initially i was sold on using the Legacy material to buff the wand and dual progress the classes, but i suspect its not really worthwhile compared to getting the 9 w/ wizard. i may just want to use escalation mage for the free meta effects or ab.champ...
looking over the creating a legacy item bit, lots of nice stuff to be had but it seems i can save all the trouble and make my own items to the same result and less hassle.
rambling done for now.. more tomorrow, i think im almost done with it.