I hate to say it but no. We could not convert load to GCash.
However, you may do Cash-In transactions vua *143# >> Gcash >> Cash-in >> Bank >> BPI which gives you BPI as your only bank of choice.
For you to balance transfer from other banks, you can use the globe website and just click My Account then access your GCash account and login to your GCash accoint and you'd have the option to transfer money from your bank to your GCash account.
Nevertheless... You can always do cashin transactions at any Globe Stores and other GCash Outlets nationwide.