Why not combine the two - i.e. radio control cars and the K9 from doctor who? A straightforward r/c control chassis would be a great basis for the K9 and there are plans for the robot doggie from places like:
http://www.tardisbuilders.co.uk/
You'd only need basic woodwork skills for the bulk of the K9, A fair bit of filler, sanding sealer and some nice metallic car paints. It'd be fun trying to soucre varios parts, washers, bits from old vcr's and things to add some of the high technozotzits to the finished model. Then you could always pull some old kids toys apart for coloured lenses, lamps and things. A basic battery circuit with a switch and a bulb for the lamps wouldn't be too tricky!
Plus I'm sure a lot of the members here would be happy to help you along the way if you started a build thread for it!
Also by using the r/c car chassis you could always swap it over for a bodyshell if you got sick of the K9! Gearing might be a little bit of a puzzle getting the motor geared down to a suitable dog walking pace, but there a whole host of small gearboxes available for rs380 and rs 540 (r/c car) type motors.
Edit: Personally I always wanted to model a full size Dalek from plans I downloaded but couldn't justify the cost of materials or time involved and the pure Geek factor I'd be weighted down by upon completion! Maybe if it was for a comission it'd be different :P