Suppose you have a brand new qualfiied plan effective 1-1-2011 (DB or DC, doesn't matter). The plan requires only 500 hours of service in the plan year to accrue a benefit (or to get an allocation). But the plan requires 1000 hours to get a year for vesting. Years before 1-1-2011 are excluded for vesting. Assume no other employer plan terminates within 5 years of 1-1-2011.

Suppose the 25% owner/HCE is now part-time, and has just turned 70 years old.

The plan has a 3-year cliff vesting schedule. Normal retirement is the later of 65 or the 5th anniversary of plan entry. Everyone employed as of 1-1-2011 is eligible 1-1-2011.

The NHCEs are all full time, but the HCE/owner wants to work these hours:

2011: 1500 hours
2012: 1100 hours
2013: 900 hours
2014: 950 hours
2015: 1100 hours

This allows the owner to accrue benefits (or get allocations) for all 5 years, but is not 100% vested at 3 years, but is 100% vested in their 5th year instead (that's NRD anyway).

Would the IRS think such a plan was intentionally designed to avoid the RMD rules for 2013 and 2014? To make it more worthwhile to consider, suppose it is a DB and the PVAB is $600,000 at the end of 2013 and goes up by about $200,000 in 2014. Could the IRS cause trouble for the plan sponsor and the HCE/owner? If so, what would they use for their basis?

Would you submit such a design for a D letter, and would that even protect them? Just theorizing/musing . . .

Wow!

Back when I learned it many years ago, I think a procedure is already in place to keep track of the RMD for non-vested amounts and then distribute as they become vested. I'm just shooting from the hip, but I always understood that to be the procedure; and think it becomes a non-issue with respect to what the IRS would think about it. I would not file for a determination letter.

With that said, let's look at all angles.

The S&P just lowered the country's credit rating (good, bad, or indifferent) for basically not raising taxes. So, the business owner would have to manage interest rate risks in that his RMD would accumulate to be distributed in a year that his tax rates are higher.

Just playing along

if it was a DC plan then 1.401(a)(9)-5 Q-8 says the RMD for subsequent distribution calendar years must be increased by the sum of the amounts not distributed in prior calendar years because the employee's vested balance was less than the required minimum distribution.
so in your example no min distrib for 2013 and 2014 but then 3 times in 2015. I'd guess this would probably be sizable enough to put the individual into a different tax bracket, so that might not be such a good strategy

Suppose it's a DB plan and the individual takes an in-service of the entire vested benefit in 2015. Is the RMD equal to the 2013 + 2014 RMD amounts based on the annuity method calculation plus the 2015 RMD based on the individual account balance RMD calculation (since it's all paid as a lump sum)?