My old GT Chucker...
Small aluminium frame, 16", with 5" risers (uncut) so can fit most people.
26" wheels, nothing special.
V-brake front, disc rear with Problem Solvers cable doubler.
It does use a chain tensioner but that leaves options open for 2 ratios.
BMX cranks 175mm currently with a 25t chainwheel but the gearing can be sorted out for whoever wants it.
Eastern plastic pedals.
reckon about £120? If interested, come by Push Cycles on Newington Green N16 to check it out.