Yeah, the way to go is to have a jailbroken PS3 (on firmware 3.55) and another PS3 that you have updated to the latest firmware.
Then you just transfer patches from your jailbroken PS3 to your updated PS3 via the Data Transfer Utility feature.
Data Transfer Utility:
You can host with just one PS3 if you get one on 3.55 or earlier, jailbreak it, insert a modded patch, then update it to the latest firmware. The downside to this is that you cannot change patches then, and if there is a new title update it will replace your modded patch.