What PDA/cellphone can act most like a pager?

[SawBones]

I'm a physician trying to get rid of my pager and just use a PDA/cellphone. Here's what I need my cellphone to do:

When I receive a text message, it needs to continually alert me and keep alerting me periodically until I respond. I have a Treo 600 now, and that isn't possible.

Through my business I can go with any of the following models:

Smart Device Treo TM700P
Sprint PCS Vision Smart Device PPC 6601
Sprint PCS Vision(SM) Smart Device PPC 6700

I know other non-PDA phones have this option, but I need to run either Palm or Windows so I can continue to use my medical software.

Will any of the above models be able to completely replace my pager? Thanks!!

[haydeno]

why not put on vibrate in your pocket

[SawBones]

It is. But I'm on call 24/7, so I eventually have to place the thing on my bedside table and sometimes the single vibration and ring tone isn't enough to wake me. Thus, I need the continual notification. Thanks for the suggestion, though.