Solo 401(k) with Husband/Wife Tax/Non-Tax Funds?

[Ian Turner]

Hi all, I'm looking for some advice on how I can best structure my retirement account real estate investments to leverage my real estate knowledge for these long-haul accounts.  

Background: Experienced and diverse real estate investor who is recently discovering Solo K and S-D IRA options for my retirement accounts. We hold and manage our investment properties under a family LLC. My wife and I have the following accounts exposed to the market which we'd like to efficiently, all or in part, invest in real estate instead: Husband: 401(k), Roth 401(k), Roth IRA. Wife: 401(k), Roth IRA.

Questions: Since we own and manage our real estate holdings under an LLC solely owned by my wife and I, are we a qualified self-employed business eligible for a Solo 401(k) program? (From what I've read, I would prefer to go with the Solo K if we qualify.)

If we were to establish a Solo K program under our existing LLC, could we roll all of our respective accounts under this structure while maintaining their respective tax and 'individual' rules? My thought would be we would have his/hers, pre-/post-tax accounts (4 different pots of money) within the Solo K and when we structured a new asset holding LLC under the Solo K, that each of the 4 accounts would simply own respective shares of that new LLC entity. Is this allowed by the IRS?

Finally, any advice on a high-quality and efficient Solo K custodian?  I've browsed a number of articles from mysolo401k and they seem to have a lot of happy customers.

Thanks!