Using a lax rebounder for baseball could work well. I'd suggest going with a baseball specific rebounder though.
You can usually scoop one up for $100 or so.
If you think a lax rebounder would work better, checkout this complete list of rebounders--It's the only one of it's kind I've found on the internet....
http://lacrossescoop.com/rebounders/lacrosse-rebounder-buying-guide/