Considering Daniel's viewpoints below, I found some cameras that match some of them, but not all of them, though I'd still need some suggestions, or help.
Well, until I understood somewhat about CHDK, the best match, first, seemed to be a FujiFilm FINEPIX JX300 (14MPX) I could get my hands on a pair for only €99 (~$133) from Germany, but now I'm a bit unsure because of the options and powers that the CHDK may unleash. This one's gotta have optics and sensors that will do the job; has the tripod mount hole. I'm not sure about the manual settings, I mean I don't what it means. If nice to have number 4 "remote triggering with no hacks" means some electronical support not the mechanical trigger we have on the standard book scanner then you may buy some controllers to it, but I don't think I'd need it as I'd prefer to have a trigger on the book lifting lever; DC power -- I hope Marcos's hack could help me out here. PTP support (is it Peer-to-peer?) I don't now, and last but not least it's quite cheap.
My additional need is to be able to make shots fast. I'd prefer some that focuses fast, and gets prepared for another shot fast, like in 3-3,6 seconds, regarding this it's indeed promising, it can take 1.2 shots in 1 second, so even if it can't do more than a few couple of frames with this speed it should be able to handle it in 3-3,6 seconds/frame. Could someone affirm me in this?
One more thing, the scanner is supposed to have one 700 lumen LED; is it enough with ISO 1600 or 3200 if ISO 3200 is "effective in S mode; (Standard Output Sensitivity)"?
This the rough plan, but I'm not sure about the CHDK. The worst is that I couldn't really find budget Canon cameras supporting CHDK on the German Amazon where I can get stuffs with a 20% discount, and I have to keep the expenses for cameras under €100.
What Canon PowerShot am I supposed to buy to get a massive CHDK support, and match all the former criteria, and my biggest dilemma is: what do I benefit from CHDK firmwares?
I don't think an Eye-Fi is a must, for example. Cheap SDHC cards even around class 10 are really cheap, around €10 each, so it should be okay to put them in the computer after each book. I don't want my to link my cameras to the PC during scan operation to store pictures there, as you still have to turn pages and pull the lever on and on, so you won't be able to handle, like a mouse or something.
Other upgrades, like faster exposition may be unnecessary if I got enough light, but this is still a question whether it's gonna be enough, or not.
Basically, if I got some good points supporting the acquisition of cameras supporting CHDK, I would like to know which I am supposed to buy, what the minimum requirement is that I've got to match.
That's all, hope someone can help me out here!
Any helps will be much appreciated, thanks in advance,
P.S.: yeah, I read somewhere that you can synchronize the video capturing on two Canon PowerShot of the same kind almost perfectly, so that you can take 3D shots both photos and videos, that may be something that I'd be interested, if I pay for new cameras now.
Why don't we compile a list of 16mp compact cameras and then do a quickie comparison in one post? I mean, our needs are easy to define.
The perfect camera:
1. Good-enough optics/sensor. (this is a moving target but it leaves out webcams/etc)
2. A 1/4 20 tripod mount hole.
3. Manual settings.
Nice to haves:
4. Remote triggering with no hacks.
5. DC power input. (Marcos outlined some hacks for this)
6. PTP support. (is occasionally implemented in CHDK)
Here's a search that finds many 16MP cameras
. Here's a really nice chart
. Let's get each interesting one, with a picture, in one post and compare on 1-5 (or other features if you like).
When we're done, it will be perfect Wiki-fodder.