Dynamically name indexes in SQL Server 2005?

As most people who work with Sql Server know, you can declare a temporary table like so:

create table #foo 
    (
    row_id int identity not null primary key,
    bar varchar(50) not null default 'YoMomma'
    );

...this will create a primary key and a default constraint on this temporary table; the names for these objects will be unique, dynamically created by Sql Server.

Is it possible to create a dynamically named index for the table after it's been created? I have a case where a stored procedure using temporary tables may be running multiple instances at the same time, and I'd like to increase the performance without risking a conflict between identically named objects in the tempdb database. CREATE INDEX command requires an explicit index name.

I am looking for a solution that does not involve dynamic SQL, just dynamic names.