Can a participant -- sole participant in a money purchase pension plan -- convert his account balance under the money purchase pension plan directly to a Roth 401(k) plan? In other words, can he terminate his money purchase pension plan and transfer his account directly to a Roth 401(k) plan?

If you mean "can he convert the existing money to Roth money?" - no.

If you mean "can he convert the existing plan to a 401(k) plan with a Roth feature, keep the old money as pre-tax money, but start making Roth contributions?" - yes.

Can the participant terminate the Pension Plan and roll his account balance to a traditional IRA. Then, convert that IRA to a Roth IRA. Then set up a Profit Sharing Plan with a Roth 401(k) feature, and then roll his Roth IRA into the Profit Sharing Plan. End result -- he has converted his Pension Plan money into Roth money and the assets are held under a qualified plan. The participant's goal is to convert his existing account balance to Roth money and be able to invest that money in real property. He would prefer to invest in the real property through a qualified plan, of which he can be trustee, rather than a self-directed IRA that will charge fees (custodial, transaction, etc.). Thanks.

No. http://www.irs.gov/pub/irs-tege/rollover_chart.pdf