From what I know, you're looking at:
- Olympus PEN E-P1 (usually available much below list; only model here with no EVF, which won't affect book scanning)
- Olympus PEN E-P2
- Panasonic G1
- Panasonic G2
- Panasonic GF1
- Panasonic GH1
- Panasonic GH2
The only really notable exceptions are the Olympus E-PL1 and the Panasonic GF2, which are cheaper consumer-style models that drop remote support. The Pannys all support wired remotes only, while the E-P series has an IR remote.
So, recommendations - if you want a wireless remote, it looks like the Pens are your only choice! Edit: I missed you prefer wired. Any of the ones I list can do that.
Overall imaging quality is very similar across the m4/3 line right now. The highest res m4/3 with a remote is the 16mp GH2; the rest are all 12mp right now. Otherwise, the DXOMark scores seem to be reasonably close to each other for all of the m4/3 cameras, with a little variation here and there. I haven't seem resolution tests for the GH2 yet, but I'd be surprised if it didn't show more detail at base ISO. However, the GH2 is also one of the more expensive models so it's probably not worth it for you.
Unfortunately, most of the cameras don't seem to be offered body-only or with a prime right now. The Panny 20mm prime has the best reputation for quality, but sells for $300+ on its own whereas the Oly 17mm goes for about $100 less. B&H
shows the GF1 with the 20mm prime for under $700 - which isn't really in the "cheap" range you're looking for. I'd take a look for refurbished E-P1s with the prime to see if the price is any better.
Edit: Checked Amazon for pricing too. They only list a couple body-only models: the G1 12mp for $350
, and the GH1
for $500. G1 would probably be better for you of the two, and might be the cheapest
The opinions expressed in this post are my own and do not necessarily represent those of the Canadian Museum for Human Rights.