I pondered that question long and hard for the past year while I researched and learned about many different printers and their strengths and weaknesses. Basically, after all was said and done, the money spent on an older Roland didn't make sense to me. I settled on a used VJ-1204 and couldn't be happier.
-IF- you already had the machine and had to pay the $2000-$2500 to convert it to solvent then yes, I would agree it would be worthwhile to do. However, if you have to buy one of those older machines for say $1500-$3000 and then pay another $2,000-$2,500 to convert it to solvent, then not so much.
I've talked to several guys that run these, and for the most part they do a good job and you can make money with them. However, there are a lot of shortcomings, and a lot of experimentation you'll have to do if you decide to go down this road.
Do your homework and run all the numbers. Good luck to you.