I use the HT820 which is both Bt and wired.
Also not sure if it helps, but here is an HTC adaptor with audio controls that takes a 3.5. But i cannot seem to find it right now. the old model had a 100 in it and the new one has a 300 in it. If i find it i will post back
Ok found a link to one of them:
http://www.expansys.com/htc/p_htc_item.aspx?i=150190
its in the UK but the model number is there