Not yet - but have been working on plans & ideas for an octagonal "gazebo" type observatory. I even have permission from SWMBO in these matters to do so!
No... but another you might find interesting is the trojans helmet "dome", easy to build. ASNSW used this for their 6m diameter dome at Mt Bowen.
Essentially its a cylinder with vertical sides rather like a water tank. The roof is in two parts - a rear section that is flat or sloping slightly so rain will run off, and a curved front section that has a simple curve with a slit in it, and a shutter that rolls to one side. As this does not involve compound curves or complex shapes it is quite easy to clad with conventional building materials e.g. colorbond.
Because the roof is flat its easy to incorporate a very strong truss across the top that can be used to lift heavy loads inside the dome.
This shape is also amenable to being built in sections off-site that can be separated for transport and quickly reassembled, as ASNSW did.
A small one would be quite easy to build in wood with hand tools.
Yes.
I had had an Octodome back in the 80's for my 12" Newtonian.
Gave much better head room than the traditional dome.
One face had double outward opening doors and a sliding roof section which cleared the Zenith. No issues, no drama.
