I heard a rumour just now that Sony are putting out an actual PlayStation phone this year. The rumour says it will use the Vita SoC and come with more RAM and be completely compatible with Vita games and will have the same form factor as the Xperia Play, but slightly larger (around 4.5"). The phone is also, apparently going to be available in non PS branding as well and will be Sony's flagship device going into the holiday season this year.
Just remember this is a rumour and not for certain, but it makes a lot of sense to me. The Vita SoC at 28nm will fit into an oversized phone (Tegra 3 is 40nm quad core, but LG and HTC are putting it into a phone before May this year) and wit PSSuite looking ready to launch Sony will want to push Vita on more than one front, making a phone version is a good way to push it. The age of the dedicated handheld is coming to an end, Sony seem to have recognised this with PSSuite, so it makes a lot of sense for them to push a phone version of their handheld.
I would buy it if they released it. Hell, I would get it as an upgrade from Vodafone when it comes due in early 2013. That's what Sony lose out on without a phone SKU for Vita, people have to actually buy it.