Watch the Dominant Soloing 2: 7 online guitar lesson by Brad Carlton from Bluesology 1
The 7sus4 chord is a great sound to use for the dominant chords in a blues progression. You have probably heard this chord incorporated into the blues by many contemporary players such as Eric Johnson and Robben Ford.
Simply substitute the major third above the root of the chord with the tone one-half higher (the 4th). Apply this substitution to the I IV V chords and start playing with the jam track. The mixolydian mode is a great scale to use over this chord.
This in depth presentation of the chords derived from a mixolydian scale and their application for creating voicings with the upper extensions will not only be helpful for constructing cool voicings but also open up your ears to countless combinations of triads over different roots.
Spend some time with these ideas and you will surely take your playing to another level.