My gf and I spend a lot of time away from one another, so I know your problem well. Some time ago, in the winter, I think, I posted on here about how I was looking for a dildo similar in size and shape to my erection, one that would make a good going away present--but not too good. After a little searching I finally found a jelly dong that fit the bill. I've forgotten the name, unfortunately. It might be longer than mine at a little over 8", but it's almost the exact 6.5" girth (like your husband's). When I gave it to her we did a blindfolded test, just to see if she could pick out the imposter. Of course she could instantly tell--something about warmth, or was it smoothness?--though she said it filled her up about the same as I do. She's been using it for about 7 months now, usually in combination with a vibrator, and with only brief interludes with the real, spurting thing.
Anyway, I was wondering if you came across the "make your own dildo kits"? There seem to be a few of them out there on the market and they could solve your problem. Making one seems like an involved process, but it could be fun--parts of it at least. Can reproduce every veiny ripple in your man's unit, to hear them tell it. Here's the address:
Make your own dildo-kits
Keep us posted on what you decide.