Here's a high-tech mystery that would even stump Sherlock Holmes: why hasn't Blackberry-killer emerged yet? This question raised its head again after I read a yet another "Blackberry-kiler" story in yesterday's Wall St. Journal that looked at new devices coming from device makers such as Nokia, Motorola, Palm, HP and Samsung. While I've seen a few people with Treos and one  guy who, for a strange reason, has a Danger hiptop, Blackberry still reigns supreme. In fact, the Blackberry has start to filter down to a growing number of non-C-level executives due to lower retail prices and the voice-friendly 7100. It's not like non-Blackberry devices are missing key elements such as mobile e-mail. The Treo 650 has even more bells and whistles, including a pretty good Web browser. The bottom line is the Blackberry is still the best device for mobile e-mail, and the new 8700c unveiled by Cingular this week should cement this status with its faster network access. What Blackberry enjoys - as does the iPod - is the hard-to-attain but valuable cool/it works factor. This isn't to say rivals won't pick up mobile e-mail market share but it is unlikely there will be a Blackberry "killer any time soon.