not so much as an alternative dot but a sideline.  once the transaction is paid for and you've paid your fees to ebay.  I put my business card in the parcel and say if they'd like to buy a similar item direct with guaranteed sale and % off the cost due to no eb overheads contact me on my email address.

I only write that when payment has been on time or if they have emailed through the course of the transaction so I know they check their emails on a regular basis.  and not for everyone as its too time consuming.

then you're not breaking ebays rules and they appreciate your offer.  an alternative is gumtree which I know is hit and miss but so is eb these days.