Does anyone make a bluetooth pen device?

My first response is “Google it, brother!”, so let’s see if that’d be a useful tactic. I’m going to go ahead and search on Google for buy bluetooth pen input device.
432,000 matches (plus or minus at least 10%, based on what I know about how Google calculates those numbers). However accurate, you’re not the first person to be curious about that type of thing. While the first match is a shopping comparison engine (which could be a good place to do some research), the second is more interesting: Bluetomorrow.com appears to have just what you’re seeking.
The rest of the matches are bizrate.com and nextag.com, both of which are shopping comparison engines. It’s annoying that they’re polluting the results as much as they are but I think when we add that magic word buy we get right into the crosshairs of their SEO efforts. Nonetheless, we can glean some useful information from their results, notably that peripheral powerhouse Wacom appears to have a matching device described in the Nextag.com match as “Wacom GRAPHIRE BLUETOOTH 6X8 PEN TABLET WITH MOUSE”. So let’s go to the Wacom site directly and see what we can find…
Their site’s a bit confusing, but some digging reveals that they have a very slick device that they sell called the Graphire 6×8 bluetooth. It looks like this:

At $250, however, that’s quite possibly vast overkill for what you seek.
Next stop, Amazon.com, where I’ll again search for “bluetooth pen” and see what comes up… There are a couple of matches, one of which is a Logitech commercial bluetooth pen (at least, I assume it’s a commercial pen: five of them are priced at over $1000, putting them in the same ballpark as the Wacom solution). Kind of a dead end.
I think I’ll go back to Google, but this time try the little-known Google Product Search. I do a search with the keywords bluetooth pen and it shows me pretty decent results, actually. The Wacom we’ve already seen, this time featured at only $209, along with the Logitech IO commercial pen. Unfortunately, those seem to be the only two matches.
Before giving up, let’s go back and have a peek at what was featured on that earlier Google match pointing to Bluetomorrow.com. Clicking on it reveals that BlueTomorrow is actually a bluetooth product directory site. Perfect! Better yet, the product in question is called the “Wow-Pen Traveler BT” and the description sounds ideal. Problem is, there’s no link to a vendor or to a site where you can buy it.
Time for another Google search, I’d say, this time for the name Wow-Pen Traveler BT. Found it! Match #1 is the domain Wow-Pen.com. Sounds quite likely!

Problem is, again, there’s too little information on how to buy the $@$#@ thing. Poke around and you’ll eventually find that Wow-Pen.com points you to wow-penusa.com, which finally reveals that a variety of well-known vendors, like Fry’s Electronics, CompUSA, MacMall and MicroCenter carry the device.
Okay, so let’s go to CompUSA’s site and see if we can find one! We still haven’t figured out the price, after all…No luck. Can’t find the wowpen regardless of how I search for it. How about Fry’s Electronics? Nope, can’t get to their site at all! MacMall? Success!! A search for “wow” on the site reveals that they have seven different Wow-Pen devices. Unfortunately, alas, darn it, none of them are the bluetooth device! You can see that the pricerange is $30-$80, however, depending on whether you want it wired or RF wireless. Microcenter offers up books from Addison Wesley on a search for “wow”. Sheesh.
This is not uncommon about the dead end you can find when researching products in the online world. I think that I would pick up the phone and call someone in the customer service department of MacMall/PCMall to see if they have any information about the bluetooth version of the Wow Pen. That seems like your best bet, unless you want to spend the $200 for a Wacom Graphire device (which I’m sure would be a great solution for you).
A general observation here is that while lots of companies have poured millions into making online shopping a breeze, it can still be surprisingly frustrating and difficult, particularly when you’re looking for something a bit out of the mainstream. Perseverance and a willingness to actually pick up the phone and call someone if you hit a dead end can be the best strategy, and sometimes, well, sometimes giving up is the most logical end to a fruitless shopping adventure.