Although not perl utilities, I found the following:

dumpasn1 (http://www.cs.auckland.ac.nz/~pgut001/dumpasn1.c )
- a ( relatively ) simple BER decoder.

asn1c ( http://lionet.info/asn1c/ )
- a set of libraries and utilities for compiling your own ASN.1 decoders. Comes with useful utilities like 'unber', which is similar to dumpasn1.

to be very useful for ASN.1 decoding work. They both require c compilation chops to get the most out of them but they've saved my skin more than a few times when testing perl decoders.

Hope this helps.