Trunk?

Thanks for the heads up.
 
I use a Givi (copy).

Paid £37 including postage and the top half is gloss black to match my R3T. 51 litre capacity (holds 2 full face helmets). I have the dual touring seat and a sissy bar so just take the sissy bar off, mount the backrest pad onto the Trunk instead (take off the nasty backrest supplied with the trunk) and the pillion (wife) can still sit back and rest. Base plate supplied just bolts onto the rear rack and the trunk quick releases just like a Givi. I'll accept that it ain't Givi quality but it looks the business and works for me - can buy 5 of these for 1 Givi.

http://www.ebay.co.uk/itm/TAKE-COVE...ycle_Parts&hash=item4d0394ca8b#ht_2547wt_1399
 
I have used the Matazu trunks and have one in the parts pile. I have found I can carry more gear if I use two travel bags facing each other with one in the passenger seat (that I use for a back rest) and the other on the luggage rack (where the trunk would mount). The second bag holds more than the trunk plus it is more convenient in that it is not fixed to the bike. When the two bags are strapped together with the passenger back rest in between them they are easy to place and remove.

Of course you sacrifice being able to carry a passenger.