VERP email addresses are often too long (> 64 characters) violating RFC and thus being rejected

According to RFC2821 <http://tools.ietf.org/html/rfc2821>:

4.5.3 Sizes and Timeouts

4.5.3.1 Size limits and minimums

...

local-part
The maximum total length of a user name or other local-part is 64
characters.

We are experiencing a problem with an important client that uses Earthwave <http://www.earthwave.com.au/> to look after their mail. Their mail gateway blocks our CiviMail mails because of this RFC violation (specifically the Return-Path bounce VERP address used in the MAIL FROM). Presumably there are other mail providers out there that do the same.

An example VERP email address CiviMail generates would be:
bounce.1.9.27.243c148ff9a0f4b0b4327c5aa4e21091833760b6-mike=example.com@example.com

It seems Moodle use VERP and complies with RFC (keeping the local part <= 64 characters):
http://docs.moodle.org/en/Email_processing

Ideally the VERP emails would be formatted in a way to ensure they complied with this RFC policy.