Originally Posted by Moldy
To me, most basslines get drowned out in modern music anyway. Unless you focus on it as a band, like RHCP did, or give the bass player a prominent role, which is more common in trios like Sick Puppies or electronica bands like Birthday Massacre.
Personally, I think you'll work out just fine.
Even when the bassline completely mirrors the guitar, you would miss it if it wasn't there. That bottom end simply can't be reproduced with a guitar, no matter how downtuned it may be.
I'm not saying it couldn't work, but it would definitely be a different sound than what you'd have if you added a bass player. I've heard a few bands that didn't have bass players, though, and it can definitely work if you work within your limitations. Maybe the guitar player(s) will need to downtune (or play a seven-string), or the drummer needs to think very carefully about where to place bass drum hits, but it should all work.