I'm after a not too pricey 14" or 15" ish frame to make a singlespeed for my girlfriend for winter. Not after spending a fortune, but something nice-ish would be... erm... nice!
Top tube length is key really something not much longer than 21.5" or 55cm ideally.
Disck compatible please, but horziontal droputs are fine as I have got myself a singleator already.
29er or 26" both fine.