The term in the final regulations is "alternative defined contribution plan". A profit sharing plan would be an alternative defined contribution plan, so it can't be established until a full year after the final distribution of assets from the 401(k).
QUOTE
1.401(k)-1)(d)(4) Rules applicable to distributions upon plan termination
(i) No alternative defined contribution plan. --A distribution may not be made under paragraph (d)(1)(iii) of this section if the employer establishes or maintains an alternative defined contribution plan. For purposes of the preceding sentence, the definition of the term "employer" contained in §1.401(k)-6 is applied as of the date of plan termination, and a plan is an alternative defined contribution plan only if it is a defined contribution plan that exists at any time during the period beginning on the date of plan termination and ending 12 months after distribution of all assets from the terminated plan. However, if at all times during the 24-month period beginning 12 months before the date of plan termination, fewer than 2% of the employees who were eligible under the defined contribution plan that includes the cash or deferred arrangement as of the date of plan termination are eligible under the other defined contribution plan, the other plan is not an alternative defined contribution plan. In addition, a defined contribution plan is not treated as an alternative defined contribution plan if it is an employee stock ownership plan as defined in section 4975(e)(7) or 409(a), a simplified employee pension as defined in section 408(k), a SIMPLE IRA plan as defined in section 408(p), a plan or contract that satisfies the requirements of section 403(b), or a plan that is described in section 457(b) or (f).
(ii) Lump sum requirement for certain distributions. --A distribution may be made under paragraph (d)(1)(iii) of this section only if it is a lump sum distribution. The term lump sum distribution has the meaning provided in section 402(e)(4)(D) (without regard to section 402(e)(4)(D)(i)(I), (II), (III) and (IV)). In addition, a lump sum distribution includes a distribution of an annuity contract from a trust that is part of a plan described in section 401(a) and which is exempt from tax under section 501(a) or an annuity plan described in 403(a).