You could try contacting Dr Nazeem Rivzi at IBMM in the UK.
He did some tests for us a couple of months ago which were very impressive.
They could even produced countersunk holes with an inner diameter of 50um.
IBMM Laser Micromachining Centre
University of Wales Bangor
Dean Street, Bangor, Gwynedd LL57 1UT, UK
Tel: +44 (0)1248 382722
Fax: +44 (0)1248 361429
http://www.ibmm-microtech.co.uk/
Andy Scholes
Acreo AB