Yeah, I'm looking at a similar 'mothballware' plan (for want of a better term) at a similar price point for something I'm currently building. I'd be interested to hear of others' experience of it.
Yes, there's a risk of it seeming like you're cutting off something people are using, but if they're that invested in it, hopefully they won't mind chipping in a modest amount now they know they really do like it.
EDIT: apologies for this being a pretty vapid comment - curled up on sofa, ill.