Currently, for rptv, the only television that officially supports a native 1080p/60 signal over hdmi is the HP DLP's. It has been reported that the new 1080p JVC HD-ILA's also receive 1080p/60 over hdmi, but for whatever reason JVC doesn't state this in their owners manual (perhaps it isn't hdcp compliant, or it isnt compatible with all products sending 1080p). Supposedly the qualia can accept 1080p/30 over hdmi, and the cheaper 60" and 50" sxrd sets from sony can accept 1080p/30 over firewire. Various other tv's (toshiba, samsung, mitsubishi) can all accept 1080p/30 (maybe 1080/60, can't confirm) over the pc input (xga i believe, maybe vga... don't use htpc so don't care) or firewire, but NOT hdmi. All other TV's, including all flat panel displays (sharp aquos lcd, others) can only accept up to 1080i / 720p, and then upconvert to 1080p. Cable, in it's current form, doesn't have the bandwidth for 1080p, and the only way to send it would be to condense it so much that it would not look much better than current 1080i, except with more artifacts due to the compression. Sony still says the PS3 will possibly support 1080p (I doubt any games at launch will though.... what motivation is there for sony since XBOX missed the 1080p boat..), and htpc will support 1080p of course. Blu-ray and hd-dvd is still very much up in the air as far as 1080p goes, at least from what I have heard.
Don't ever ask customer support questions about a certain product their company carries. I'm pretty sure they just have the same manual that you can download off the internet, and if it isn't in there they aren't gonna answer. you're better off scanning forums until you find an owner, and then ask them to answer your questions.
Happy HD-ing.
Hanse