There are a lot of misconceptions about BTECs...
I teach Level 2 and Level 3 BTEC in Performing Arts. IMO, it is a more appropriate course for Performing Arts than GCSE. It is almost completely practical, and gives students a lot of "real" experience. Some GCSE Drama syllabi are more like English Lit with a bit of performance thrown in.
Level 2 BTEC can be "equivalent" of either 1 GCSE (BTEC Certificate), 2 GCSEs (BTEC Extended Certificate) or 4 GCSEs (BTEC Diploma) At my school, we do BTEC Certificate in 1 year, and Extended Certificate or Diploma over 2 years, depending on the ability of the students.
BTEC Level 3 PA follows a very similar pattern to Level 2, but I take students in VI Form who haven't done Performing Arts at all at KS4, and provided they have an interest in the subject, they tend to do well.
Crabapple99 - I'm afraid you know very little about it when you say that "Many A Level courses just don't accept BTECs full stop". That is simply not true. The majority of universities are also fine with Level 3 BTECs provided that they are appropriate to the degree course being applied for.
Performing Arts is one of the BTECs currently undergoing change, and as from September 2012, will include an element of external assessment which is currently not there. This will not change things massively in centres which are doing things properly, and will bring it in line with the majority of GCSE Drama syllabi, as the external assessment will involve an external moderator watching a performance for one of the core units (most likely Acting Skills and Techniques)