If you were planning to buy a smartphone from Verizon Wireless soon, you may want to hold off for one more month. It looks like there are a number of high-end smartphones that are set to launch this spring; at least, according to a tipster who leaked an internal document to Phandroid. The leak suggests that Verizon Wireless will release the Casio Commando, an Android powered smartphone, and the Samsung DROID Charge — capable of running on Verizon’s 4G LTE network — on April 7th. The next week, Verizon Wireless will purportedly launch the Sony Xperia PLAY and the Windows 7-powered HTC Trophy. On April 28th, the HTC DROID Incredible 2 may also make its debut. Verizon Wireless’ other 4G phones, including the LG Revolution, Motorola BIONIC, Motorola DROID X2, and Samsung Galaxy 2 (presumably the Galaxy S 2), and are reportedly scheduled to launch in May. Again, this is all speculation, and given that the source’s Excel file looks a bit shoddy, we wouldn’t place too much stock in this… but the timing does make sense.