All that all of you talking about implementation MMS support is dirty hack.
Just look the truth. In real situation to implement it we should consider next requirements:
1. MMS is not unique service that requires separate interface. Just see the OMA and 3GPP's R5 requirements. All operator's services should be provided thru IMS. MMS is one of. So, the MMS feature is SIP.
2. IP-address spaces of Internet's connection (Inernet's PDP or Wi-Fi) and operator's PDP could be the same. There is collision.
3. MMS PDP usualy have separare DNS (if used to resolve HTTP Proxy / WAP 1.2 Gateway address).
4. 3G network and GSM supports up to 2 separate PDP-conexts at the same time.
5. WAP-Push indicators has specific message type and i'm not sure that messages of that type will be stored at the event database.
So the best idea is to implement multi-instanced TCP-stack like it's implemented at Symbian and qualified support of WAP-Pushes. After that we could speak about MMS frond-end and rendering.
I know nothing about implementation of multi-PDP at Android but the Windows Mobile implementation is too dirty. As i understood the iPhone implementation has second TCP stack for MMS.