Re: Scanning B&W negatives
Unfortunately this might not be the answer you're looking for. Epson makes some flatbed scanners that will also scan 35mm and/or medium format negatives but the scan quality won't be as good as a dedicated film scanner. Depends on how good of a scan you need, I guess.
The dedicated film scanner route starts at about $300 for a 35mm but much higher for a medium format (not knowing how big the "larger" negs are). Don't worry for this project about getting a scanner with Digital ICE which automatically removes dust, because it doesn't work with B&W anyway.
The learning curve is pretty steep but I feel like I'm starting to get a handle on it. The big secret is to scan the B&W film as though it's a color transparency (slide) and then convert it to B&W and "invert" it in Photoshop. You'll really need a can of compressed air to blow the dust off the negs before you scan them too.
Re: Scanning B&W negatives
That's the trick - scan in color, then convert. This is one of the most critical things for scanning B&W.