Just picked up an old steel framed 10x6 to replace the defunct polytunnel on the plot.... welded steel panel frame foro each side (they weigh a fair bit) missing a fair chunk of the glass (not bothered, would have been putting 4mm twinwall on the roof anyway), but it has all the clips and even full-length shelves for both the long sides and a pair of single-pane vents in the roof... I'll add my spare pair of louvres left over from the big one at home and a double roof vent on an auto .... £5.51 on ebay
An extra 60 square feet of glasshouse adds approximately a third to my covered space, so pretty good for stacking up more propagation in the spring to do an extra car boot or two, I'll be able to use it to grow extra plantings of marginal outdoors things like Oca, Yacon, lima and giganda beans as well as pushing some autumn and winter harvests of things like peas, fingerling carrots, baby beets, fennel etc.... sort of the reverse of the tender stuff, these will start off outdoors in modules and come in for planting out... maybe try some winter spuds...
Future plan is to move the rhubarb and stick another 6 feet of greenhouse on this to make a 16x6 which will open up the possibility of maybe a grapevine or an indoor apricot....