markee174: "Haven't you just argued in favour of releasing the code under both a GPL and a non-GPL license?"
Not necessarily. Selling services around a wholly GPL product is perfectly possible. Dual licencing may make more sense if you want to value-add software, but you need copyright assignment.
"The GPL version encourages people to look at it and investigate the source code. The serious customers will want the non-GPL version and support - the GPL version just provides a better way to reach them."
Except the GPL doesn't allow you to distinguish based on usage, so commercial customers who don't want support can use it without paying a royalty.