Hi Alex,
Yes i've looked at a few different designs, particularly Reiner Vogels:
http://www.reinervogel.net/index_e.html it was these that made me want to build my own in the first place. But i really feel uncomfortable with how exposed the mirror is, not only in regards to dew, but dust and its general integrity. And that you cant put a shroud around it.
But now after a chat with Ian (stringscope), I'm thinking that i may be better off rebuilding my current solid tube 12" GSO dob. There are a number of factors that have changed my mind. Firstly the difficulty is significantly reduced, purely by the reduced mirror size. It will be easier to achieve the 400mm max height. It will be much cheaper, given that i already have the primary mirror. One thing that really stuck me was that John (astronut) said that you don't really get the wow factor when going from 12 to 16 inches. Sure its there, but perhaps not quite as much as one might think. In fact, the one time i did look through a Meade 16" i was not as blown away as i might have expected. Maybe if i used a premium mirror, but not the one i intend on using.
In other words....bugger it. LOL
I'll have another poke around the internet for dob designs, but i think ill stick with the traditional design...unless a forum member can persuade me again lol.
FYI I need a full bearing so i have somewhere to attach an alt encoder for my DSC's...this was the reason i left the low, open profile mirror box design.