BorderWeb,
I work closely with several churches, never seen one so unreasonable. I understand your side here really, but that is more than 'prudish', it is a lack of understanding of technology in any form. I am sorry the whitelist option stopped working, I wasn't aware of this being the case.
Every place, and person is different, but in the past with churches I've done local gateways that handle this, and make a lot better money in service than hosting side. So especially if these are local I have another optional suggestion to you to possibly study up on and offer for them outside the realm of hosting, but could be bundled as a value add service package.
The ClearOS is a good project, and product:
http://www.clearfoundation.com/Software/overview.html
I used to bundle services like this using small custom built, and realtively cheap miniitx motherboards with multiple nics to make them onsite universal threat management services. These filtered websites, emails, etc. These days you can even get them that have built in wifi systems so you can have main and guest wifi hotspot services as well. So you load this up, and help them management it monthly, provide the back end email and site services, the base free one works quite well these days, it isn't the platform I used to use (I used ipcop and some customized addons way back), but one addon to highly consider would be the $100 year content filtering updates.
Not sure you'd be up for this, but just something maybe to consider!