Jan, because both Fabrico and Pigma pens are designed for use on fabric, you really shouldn't have trouble with the ink bleeding. Sounds like new pens will help.
Another option would be to use Fabric Ink. You can order it here:
http://www.jukeboxquilts.com/store/allPurposeInks.php
It's the same "ink" as in the Fabrico markers, but you use Fantastix to apply the ink, and can control the amount you apply.
Here are some helpful hints for using the inks:
http://www.jukeboxquilts.com/hints/allPurposeInks.php
I used these inks to create a quilt using my grandchildren's artwork for designs: (click two times on the photo for a closer look)
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Bridget uses the same inks for her gorgeous flower quilts:
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See how she does it starting here: [url]community/my-profile/Bridget473[/url]