I have been shooting 5x4 for a little while, and it's great. But... I really like the 5x7 aspect ratio.
The good news - my lenses cover 5x7 with some movements, and I can get a 5x7 conversion kit for my 5x4. So in principle I could step up fairly easily.
The bad news - 5x7 colour film is hard to find (although not impossible), or you can cut 10x8. 5x7 double darks are really hard to find. 5x7 processing isn't that easy either - I'm in the UK, and my favourite labs don't offer it (although I believe there are others that do).
My question to the wiser and more experienced folk is: do the difficulties make 5x7 colour impractical, or can one get over the issues with a reasonable amount of effort? (I know 5x7 B&W is easier, but that isn't my bag.)