I was in a similar position recently, went for the second hand frame option as I had decent wheels and everything else bar chainset, picked up a decent Dolan for £120 ish, if you do this you just have to look around a bit and be patient as well as here and e bay I check TT forum as they come up there occasionaly (mrs got a dolan with chainset chain seat pin in realy good nick of there for just over a ton and they had a ex Jason Quely keirin frame on there for £190ish recently). But it was a close call between that and a full bike, if i hadn't had decent wheels i'd have gone down that line
I was in a similar position recently, went for the second hand frame option as I had decent wheels and everything else bar chainset, picked up a decent Dolan for £120 ish, if you do this you just have to look around a bit and be patient as well as here and e bay I check TT forum as they come up there occasionaly (mrs got a dolan with chainset chain seat pin in realy good nick of there for just over a ton and they had a ex Jason Quely keirin frame on there for £190ish recently). But it was a close call between that and a full bike, if i hadn't had decent wheels i'd have gone down that line