Not currently. Personally, I would love to see the option to add an unlimited number of LS accounts to a forum account, but I don't see that happening anytime soon.
If you have a gmail account, you can use a really nice feature of it that will allow you to re-use the email quite a few times. The feature is that you can add a period to any point in your email address name, and it will still go to your normal email address. So, if your email address was
myemail@gmail.com, you could use any of the following variations and more:
my.email@gmail.com
m.y.e.m.a.i.l@gmail.com
m.yemail@gmail.com
mye.mail@gmail.com
myemai.l@gmail.com
my.e.mail@gmail.com
And so on. I use that feature a ton and it is quite awesome. There is another similar feature that works with gmail to make a limitless number of variations as well, but it isn't accepted by all sites as easily as the period trick is.