Strakk: apologies for the delayed reply...
I agree with witzendoz; the 3700 is one of the "sleeper" console bargains out there.
$2000 CDN seems a bit high, you may try to negotiate with the seller.
I paid $1500 USD in 1999 for mine (with full meterbridge and 3 fully wired Switchcraft TT patchbays). It was used by a music college professor to mix keyboards and lived it's life locked behind glass. So, it was in pristine condition.
Tascam had a bad rep back in the 70's, but by the time they produced the M3700 in 1992, they had advanced far past those early days.
It works flawlessly and sounds great. That speaks for itself, as I have been a studio tech for 40+ years, and have used many different recording devices, from simple tube mixers up to consoles costing hundreds of thousands $$$. ( of course, that is an opinion and would depend on many other factors) To further qualify that it sounds "great"... let me compare it to a Focusrite, for example. In my opinion a Focusrite mic pre such as an ISA428 has no "sound" of it's own. That is, it is very clean and neutral. The M-3700 is like that. Many other consoles and or mic preamps have a distinct sound. While that is desirable in some cases...that "sound" once imprinted to your recorder will always be there. Having a clean sounding console let's you be more versatile in your choices using outboard mic preamps. Once you have those sounds you want during the recording process, you have a "clean" console to mix with. Just makes better sense in the overall recording picture in my opinion.
Remember the movie "O Brother Where Art Thou" several years ago? Ralph Stanley recorded most of his albums in a studio using an M-3700.
It is not too big physically, so it fits very well into a small room. I use mine to control my audio software thru MIDI.
While that use is limited, I prefer using the faders on the M3700 to mix instead of using a mouse.
The -10 levels are not an issue at all. I interface mine with a 3M 24 track analog machine and an Alesis HD24 HDR. I rebuilt mine in 2003 ( just because I wanted to ) by replacing all the caps in every channel and upgrading the chips to Burr-Brown FET chips ( I don't know if those are still available) The original chips were pretty cheap, and while they are OK during normal use, if overloaded they can sound pretty bad. The FET chips tend to overload in a more "pleasant" manner. Sort of like the comparison to tubes over solid state equipment. (It's that even and odd harmonic thing...)
I think the original price with full meterbridge was $20,000 USD