There are only one or two that are actually DIN sized themselves. As said above there are adaptors for most because they are a pretty standard size, it's just a smaller standard than DIN.
odly enough the debth of the radio could be some concern as with some dashes it is quite tight even with a normal stereo so it would be provident to check what debth you have before deciding on a model.
Incidentally as a radio ham i have found at my expence the police have a very dim view of people using hand held microphones whilst mobile/driving , it is possible to have a hands free setup fitted to virtually any cb or two way radio ( i have made many) .
some radios have a VOX system this may be a good thing to go for but they can be a real pain as the mini can be quite noisy and would make the radio transmit when you least expect it i.e. when your swearing at a dopey pedestrian or road user !! or even when you take a phone call on your other hands free kit
the proper hands free kit has a switch you can velcro on to where ever you want to (gear knob) and a remote microphone which clips on to the sun viser or rubber trim on the door.
I have seen some quite useful bluetooth kit (blue parrot) appearing on the american market now but it hasnt reached old blighty yet the truck drivers use it on their cb radio gear.
some sites for equipment
Fleebay
nevada (southampton)
truck king (watford)
Martin lynch (South west london)
walters and stanton (london)
hope this helps
shawn