NOW someone understands what I went thru during tech support for the BB platform ... a VERY demanding user that MUST have his BB working at ALL times and a resolution, yesterday!
I've not come across 'sonicwall firewall'; but are you talking about a PBX setup? Cisco I think has VPN client on BB, I know Avaya does, and there supposedly is another. You might have to REALLY dig to see if the SIP on your BB8820 will implement with the 'sonicwall firewall' you have for VoIP and get PBX working. Also the Telecom techs might not like the extra work, thats for sure. If you've got all the contacts & info willing to help you get it working, maybe an email to RIM would help you get a solution working.
I'm considering the Nokia E71 due to the breadth of consumer applications (I'd like the Facebook on S60 to debut soon), and games, along with better music control. However, with the Bold supporting so much and it's 3G HSDPA appeal (along with DIVX support) it's possible 2008 will give the BB's a HUGE uprise in more consumer focused apps than EVER before.