I had similar width restriction problems when I upsized form the SR4.
I have the spreadsheet still lurking o nthe PC at home - let me know the width of your door (& length of the garage) & I'll filter the list & post the results. I should add the list isn't exhaustive, but will give you a good start.
Humber do a selection of Sub 2.1m beam boats - the O-Pro (2m beam) handily tells you in it's name it will go through a garage door, and from memory comes in at 5m for the smallest one. The Attaque / Assault (I always get them confused- one is the old name for the O-Pro, the other is the shallow V hull) are from memory also 2m beam http://www.humberinflatables.co.uk
You then have the Avon SR4, and again from memory the SR4.7 is also that width....if you can find a 4.7!
for the Seariders
for the "leisure" stuff.
Ribcraft also have a sleection of suitable sized stuff, I know there's a 4.7, but best look on the website for details.
There are others out there.......