Retirement account options

[One day at a time]

I have a Roth 401k with my current job.  I do a bit of consulting work on the side.  If I wanted to invest in a second retirement savings vehicle, I am wondering if there is anything beyond the traditional IRA?  Could I put the money in a SEP for the consult income?  In particular, I am trying to figure out if there are options that don't have the traditional IRA funding limits. 

Thanks

[dualstow]

Could I put the money in a SEP for the consult income?

Since I qualify for a SEP, I have been socking money away in a solo 401(k). Check with specialists to see if you're eligible, but do look into the Solo. Nice high limits.
(So far, I have a Roth IRA, the solo 401(k), an old traditional IRA and am about to open a Roth 401(k). Of course, I can't contribute to everything every year).