Update: a new one that's only one character too long 
sub b1{M1E3D500C100L50X10V5I1=~$_;$'}

[download]
Not any more. ;-) 
sub b2{M999D499C99L49X9V4I=~$_+$'}

[download]

Update: As described in The 10**21 Problem (Part I) this one is four strokes shorter: 

sub b3{XCMVLD=~$_;"1E@+"%9995}

[download]

In reply to Re^2: Golf: Magic Formula for Roman Numerals by eyepopslikeamosquito
in thread Golf: Magic Formula for Roman Numerals by eyepopslikeamosquito

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