I've got two of them. I ordered the one without the pierced top tube and received the one with the pierced top tube.
Unfortunatley it was also damaged in transit, ie bent dropout and a dent in the top tube.
I contacted the seller, (his name is John) and he was very apologetic about the mix up and sent out another frame to replace it and let me keep the damaged one.
I've straightened out the mech hanger and the dent in the top tube certainly doesn't make it unrideable, so I've effectively got two frames for £30 including delivery.
Anyway back to your original question about what they are.
The pierced top tube design looks very much like this Protrax:
And the none pierced top tube design looks like this Protrax:
I've no idea exactly what year they are but I'm reckoning early to mid-nineties, based on the canti noodle on the pierced top-tube design.
If anyone else can pin down the exact year that'd be great.
More details:
Pierced T-T design (like the yellow Tufftrax): Frame number: A707002155 Wieght: 2.6kgs
Non Pierced T-T design (like the Purple Tufftrax): Frame number: C06 1018 Wieght: 2.1kgs
If you're thinking of buying one then, despite my troubles, I'd recommend them for the price. They are in good, new condition, but you'd have to consider a respray or powdercoat though as the paint is pretty thin.
Might be worth contacting the guy to see where they all came from and whether he knows the history of them.