Mucho Gracias! Works like a charm, and really fast. Here's the code:

VB Code:
  1. 'Declarations
  2. Private Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" ( _
  3.      ByVal hwnd As Long, _
  4.      ByVal wMsg As Long, _
  5.      ByVal wParam As Long, _
  6.      ByRef lParam As Any) As Long
  7. Private Const EM_GETLINECOUNT As Long = &HBA
  8. Private Const EM_LINELENGTH As Long = &HC1
  9. Private Const EM_LINEINDEX As Long = &HBB
  10.  
  11. Private Sub BreakLines(rtb As RichTextBox)
  12.  
  13.     Dim i As Long
  14.     Dim xPos() As Long
  15.    
  16. 'Remove padding
  17.     rtb.Text = Replace$(rtb.Text, vbCrLf, " ")
  18.     Do
  19.         rtb.Text = Replace$(rtb.Text, "  ", " ")
  20.     Loop While InStr(1, rtb.Text, "  ")
  21.     'Count Lines
  22.     ReDim xPos(SendMessage(rtb.hwnd, EM_GETLINECOUNT, 0&, 0&) - 1)
  23.     'Get Indices
  24.     For i = 0 To UBound(xPos)
  25.         xPos(i) = SendMessage(rtb.hwnd, EM_LINEINDEX, i, 0&)
  26.     Next
  27.    
  28. 'Insert Hard Breaks
  29.     For i = 1 To UBound(xPos)
  30.         rtb.SelStart = xPos(i) - 1 + i
  31.         rtb.SelLength = 1
  32.         rtb.SelText = vbCrLf
  33.     Next
  34.  
  35. End Sub