Here is a set of spacers that you can bolt on your commer and make the wheel track wider and give you commer better road holding on those corners!!
http://www.motorsportworld.co.uk/frame-detail.asp?PAGE=/manranges.asp
To get the wheels further out(wider track)thats not expensive really as there the real deal.They bolt to the original hubs with nuts and then the wheels bolt to the hub on a seprate set of studs to prevent extra stress on the standard studs there also hub centric so if you fit cherokee wheels to your commer they will bolt straight on with no messing about!!
You can get the wheels out about 30mm a corner with 7j wheels,im using 185/55/14inch tyres on minilites to give it a bit of a euro look. So thats 60mm an axle ive ordered me a set of H&R wheel spacers from germany should be here in about a week so will let you know but ive had a measure up should go straight on not cheap though the ones i put the link to are wrong pcd you need 5x127pcd [8D][8D]
There is pleanty of room if not you could fit some rubber lock stops on the steering leaver that comes through the crossmember.Im sure there is enough room wait till you see daves van next if your worried about room his wheels must be atleast 17inch!!