Buying and holding real estate in a IRA. What are rules?

There have been previous postings on RE investment. IRA investment in RE are subject to prohibitied transaction rules of IRC, e.g., can't use IRA to by home for owner, can't use borrowed money to purchase home, must find a custodian to hold title to RE which is expensive since few custodians will accept RE and using IRA to own RE eliminates tax advantages of RE including deduction for depreciation, expenses, property taxes, no capital gains, etc. Since IRA is responsible for paying all expenses of RE such as property taxes, lawyers, etc. there must be sufficient cash reserves.