Often times, number or formula custom fields are used to show currency amounts, percentages, as well as "thousands separator" formatting. But they can only display as plain numbers (with decimals).
Add the ability to enhance number custom fields such that users can:
  1. Define a prefix/suffix character or format
  2. Define "thousands separator" format (none, comma)
Some examples....
== Example 1 ==
Name: "Invoice Amount"
Type: Number
-- Format --
Prefix: $
Suffix: None
Separator: Comma
Example format: 100000 => $100,000
== Example 2 ==
Name: "Product Weight"
Type: Number
-- Format --
Prefix: None
Suffix: kg
Separator: Comma
Example format: 10000 => 10,000 kg
== Example 3 ==
Name: "Percentage sold"
Type: Number
-- Format --
Prefix: None
Suffix: %
Separator: None
Example format: 99 => 99%
== Example 4 ==
Name: "Days until kickoff"
Type: Formula
Formula: DAYS(NOW(),field("Kickoff Date"))
-- Format --
Prefix: None
Suffix: days to go
Separator: N/A
Example format: 56 => 56 days to go