Tough call, recommending a tool for someone else, but if you go the authentic Dremel route, I'd say the 4000is the best
http://www.amazon.co.uk/Dremel-4000...F8&qid=1422548463&sr=1-3&keywords=dremel+3000. It's a fair bit pricier than the 3000 but one of the things that makes sense for the extra money is that it has electronics built in to maintain the speed you've set under load. That should help when meeting irregularities as you do while working thru woods. having said that, with a light touch and care, I've never hurt my little 3000 or my Li-Ion version, even while making a rebate through an old oak box, to hold a base on. So if money is tight, you could spend around half (or less) for the 3000 and I doubt it would hurt, but the 4000 is more designed for the job.
The Makita that Marcros suggests, is the same base unit as mine, and it's a fantastic motor and beautifully made bit of kit. There is a plunge base available for it (cleverly the router slips out of it's base and can be popped into others) and I checked for you, you can actually get double fluted 3.2mm straight cut router bits for it's collet
http://www.screwfix.com/p/trend-2-flute-straight-router-cutter-shank-3-2-x-12-7mm/8789f but yes, even though it's great kit, your view is a bit more restricted with it than with a Dremel type tool, and it's substantially heavier (tho capable of much more heavy duty tasks and very light for it's capabilities)
Luthier forums and suppliers often talk of the Proxxon multitool as being very good, precise and robust, it certainly has a more powerful motor, but it doesn't look like it has the threaded fore-section, so it won't be compatible with the Dremel accessories.
The link whiskywill linked does the Dremel compatible brass/alu one at a reasonable price with optional extras, might do you nicely. I know it's what I'd go for, should my own base ever fail - it's even got the one thing my own is missing - in fact they're almost all missing, even the £200 makita CX4, a micro-depth adjustment.
http://www.luthiertools.co.uk/products.html At £35 I'm tempted to just pick one up, it looks like a good clone of the top end stewmac that Marcros mentioned.
Nic.
EDIT: Based on one of the nice features of my black and Decker one, I'd suggest you put a layer of low friction tape under the base of it, to stop from getting scratches on the surface of the wood you're working on, especially since that one has a metal base.