Im looking at my process MIDI effects --> Velocity panel and I can't find how I can tell SONAR to set a minimum velocity....say 50, where any note under 50 is bumped to 50

What about the "LIMIT" parameter.  You can set a minimum and maximum:
 
http://www.cakewalk.com/D...lp=EditingMIDI.57.html
 
 
 
 
edit: fixed link - sc

I know 2 ways:
1) (using included processor)
  a) select MIDI clip in question, from "Process" Sonar menu select "Find/change..."
  b) press "None", click on "Note", change "Velocity Max" to 50, press OK
  c) set "Velocity Min and Max" to 50
  d) (optional) enter preset name and save settings for future use, you can then just select it next time instead of (a-c)
  e) press ok
 
2) (using external processor): http://www.azslow.com/index.php/topic,275.0.html
  a) either insert MFX into MIDI track FX bin or right-click the clip, "Process Effect..."/"MIDI Effects"/"AZ Velocity"
  b) open the effect in case of MFX on the track
  a) Starting from strait diagonal line (the default, double-click to revert into it), draw strait horizontal line starting "In: 1 / Out:50" till "In:50 / Out:50". Tip: keep mouse button pressed to find correct initial Out position and for modifications. IMPORTANT! Leave "In: 0 Out: 0" as is!
 
These methods comparison:
* (1) is standard, (2) requires external tool
* (1) can work offline only, (2) can work offline for clip or online on track, including live play
* (1) is more powerful for other kinds of replacements, (2) is more flexible in velocity curve definition
 
PS. I must admit that in this particular case, slyman's solution is simpler then my
 

You can also use the event filter to search for and select all notes with velocity in a given range and then apply the change.