(farm partnership comprised of two couples, and one couple assigned their interest to the other couple who then defaulted on partnership debts; couple that assigned their interest then filed involuntary petition against partnership; bankruptcy court determined that cause existed to have trustee appointed because of assertions of fraud and defaulting couple had farmed the partnership land rent-free, and partnership was leasing land for less than fair market value; interests of creditors merited trustee's appointment under 11 U.S.C. Sec. 1104(a)(1)).