Why not cast on site? A silicone mould is light and durable, and while pouring concrete isn't easy, I don't think it's prohibitively challenging. You could ship the mould, cast on location, and return the mould for a refunded deposit.
Because that won’t be cheaper. Yes shipping statues is expensive, but setting up an impromptu workshop in your garden then tearing it down only after one cast is going to cost even more.
I assume you wouldn't just cast one thing. Obviously it's not ideal if you just want one statue, but the concept scales well. You could get two moulds and do a dozen statues over a couple weeks.
You're going to have a hell of a time getting very many objects out of a mold meant to hold concrete for an interesting lawn ornament. Especially when in the hands of a renter who's probably by definition never used the process.
I dunno, some light searching reveals that they lots of latex moulds for lawn ornaments are for sale on Etsy. It seems like these things are out there.
