Hi Andrew,
If you like that model, there's 2 on ebay. Not solid gold though.... They ask about $1,500 for 1 of them, so the solid gold one might cost a lot more than that.
http://www.ebay.com.au/itm/1975-ALL-STAINLESS-STEEL-OMEGA-CONSTELLATION-LED-WATCH-/350521048985?pt=Wristwatches&hash=item519caebf99#ht_2376wt_932
http://www.ebay.com.au/itm/OMEGA-CONSTELLATION-RED-LED-WRIST-WATCH-A-F-/310370317568?pt=UK_Jewelery_Watches_Watches_MensWatches_GL&hash=item4843833500#ht_500wt_949
Regards,
Michel