IEM rack mixer

So I've been charged with building an IEM rack for the first time. I know exactly what circuitry I need, but I'm looking for advice on what boxes exist for this purpose.
The band has a drum kit, bass rig, elec guitar amp, keys, violin DI, sax mic, trumpet mic, vocal mic. They play mid size venues with everything reinforced.
We want the ability for up to 8 of the house input lines (for example: vocal, violin, sax, trumpet, keys, overheads doubling as ambient) to go through our rackmount 8ch mic splitter, with the iso side feeding IEM transmitters and the direct side feeding the stage box via a decent size 8ch XLR snake we'll leave in the rack.
The big question is: what should go between the 8ch split and the IEM transmitters? We currently have only 2 interested band members, but room for future growth could be very nice. And we're talking STEREO mixes to all transmitters.
Most little 8ch mixers I've seen don't have stereo aux sends, so I don't think one of these is ideal at all. Instead, maybe some sort of 1U single-bus mixer per transmitter? And the iso outs from the rack split would y-split into each personal mixer? Basically, such mixers would need literally 2 knobs per input: level (with built-in preamps) and pan. 2 band EQs would rock, but not a dealbreaker.
OR - should all the preamps and EQs reside in one master unit (like a normal 8ch mixer with direct outs), and y-split each channel at line level to these "per transmitter" mixers which would handle level and pan without preamp duty?
Obviously there are giant matrix mixers designed for this purpose but I'm on a "low as possible" budget here.

As I read your thread title, I thought "Crest XRM," as it's perfect for what you're after. I believe it's discontinued. I'm not sure what defines cheap for you, but the Crest is more expensive. I see a couple on eBay for $1300-1500.

That's exactly the kind of board I was thinking of, but it's overkill... 12 x 12 when I really need 8 x 4+, a bit more EQ than necessary, 48v can come from the house, etc. It's certainly a great solution overall, but less stuff for less money would better fit this bill. They want to keep it under $1000 for the whole rig. Used is fine though, so figure maybe $1500 new, but that's with the rack, snake, everything.
With the modular method I can get a split and line mixers for about $200 a pop, so that's $600 (for 2 stereo mixes) plus maybe a $100 snake and a few hour's worth of Y cables. But that leaves me searching for a head amp... 8 pre's (maybe with EQ's). I feel like every time I search for rack preamps I end up with either boutique studio gear or converters. Any suggestions for Mackie-level preamps -- just 8 preamps?

From far left-field---> MOTU 828/896 mk3? Or Presonus 1604?
I've been using my 896mk3 as my personal band's mixer for a while using wired IEMs.
JP

Used Crest XRM or A&H MixWiz Monitor (hard to find - once you have one, you hang on to it). Plenty of channels, built in splitter, plenty of mixes (stereo or mono).

Ended up recommending the XRM so we'll see how it goes Thanks everyone