I was cleaning the basement last week (i.e., moving stuff from one pile to the next) and I unearthed an old 1/72 Airfix castle (I think Dave gave this to me but I wouldn't swear to that--might also be from Bruce?). Anyhow, I almost tossed it into the recycler and then though I could make some 28mm camps from this.
A few minutes of cutting and breaking and viola, two partial castles to use as camps. The camp pictures above and below (with some 28mm HaT Anglo-Danes conversions) is a legal DBA camp (as far as I can tell).
The camp pictured below is a legal HoTT camp (and could be used in DBA if you hung some of it over the edge of the board although I've never seen anyone at our club balk at a camp).
You can see a bit of damage on the left side of the picture below (late night cutting to make it fit on the base) that I need to fix. Maybe some climbing ivy. Also, I think these could use some troops to garrison them, although that reduces their utility.
Up next: I'm making slow progress on some 15mm DBHx AWI guys. I may push up some 28mm seige engine crews so I can complete those bases. Thereafter, who knows. There is quite a stack of 15mm armies to be done. And I won some 28mm medieval guys at the silent suction I may do quickly to morph my medieval army some more.