A Battleswitch is similar to a relay in the sense that it is just one of those off-the-shelf components that everyone buys. Making one wouldn't be worth the hassle/cost/specialist equipment.

I've never used a battleswitch or relays for a lifter but as far as I'm aware, if you're controlling your lifter with those components you will need, two battleswitches and two relays to provide up and down motion. The battleswitches themselves contain relays but these aren't likely to have a high enough current rating to control whatever you're using to actuate your lifter (as a question, what are you using to actuate it?) so you'll need to have one battleswitch activating one bigger relay to move the lifter up, and the same with the other battleswitch/relay to move it down.

Alternatively you can get a dual battleswitch from Technobots that would save you having to buy two separate individual ones: http://www.technobotsonline.com/doubles ... ay-8a.html
You would still need two individual larger relays to connect to though.