Hi Geoff,
If I could offer a solution that meets all your functional requirements (if not in the exact terms you stipulated):
Please consider a derivative of the German equatorial design with an extended polar axis such as the ASA Direct Drive DDM160
http://www.astrosysteme.at/eng/mount_ddm160.html
To avoid duty of care issues associated with counterweights, simply orient the telescope such that it operates past the meridian with the counterweights high in the air, like so:
http://www.apm-telescopes.de/media/i...%20inch-22.jpg
This is a turnkey approach with a proven track record boasting professional level reliability that will work with your existing 16" OTA and is easily upgradable to a much larger instrument if and when required.
If you wanted to save money, you could basically achieve the same thing using a generic German equatorial head with a custom pier that gave the same clearance for the OTA. A slightly modified AP1200 would be quite a bit cheaper but do everything you required without the public safety issues normally associated with counterweights. (you can pick them up for under $10k landed in Aus if you're smart about it)
regards,
~c
PS: Ice in space might not be the best place to solicit advice on such matters.