In reply to CurlyStevo:
One of my favourites for remoteness (It's a long winter's day as well) is to start at Strathan in Glen Dessary, cross the Feith a Chicheanais from Glendessary lodge and climb Sgurr Mor. Then head west over Sgurr Beag, An Eag, Sgurr nan Coireachan, Garbh Chioch Beag, Garbh Chioch Mor and Sgurr na Ciche. Descend the Feadan na Ciche down to Glen dessary and long walk back to Strathan. With some bivvy gear you could descend from Sgurr na Ciche down to Sourlies bothy, overnight there then back on the track to Glen Dessary.
A nice "two pubs" walk is Cluanie Inn to Kintail Lodge hotel over Aonach Mheadhoin, Sgurr a Bhealaich Dearg, Saileag, Sgurr nan Spainteach, Sgurr na Ciste Duibh, Sgurr na Carnach, Sgurr Fhuaran, and Sgurr nan Saighead. Neither of these has "techical" bits but both offer narrow ridges and fantastic views.
Nearer to the central belt you could do Beinn Eunaich, Beinn a Chochuill, Stob Diamh and the Cruachan ridge to Stob Dearg(Taynuilt Peak).
The latter two walks involve some public transport logistics. The first would unfortunately be a WEE bit outside your mileage parameters.
As previosly mentioned the Starav round over Glas Bheinn Mor and Stob coire Albannaich are good in winter.
A final suggestion - but again a bit longer than your 6-12 mile is the Blackmount traverse starting at White Corries over Meall a Bhuiridh, take in Creise ocer Clach Leathad and on to Stob Ghabhar. Descend Sron nan Ghiubhais ridge of Stob Ghabhar down Coire Ba to Ba bridge then take the old drove road(part of West Highland Way) back to White Corries.