Yes, you can do that:

To display the donation amount field for an item in the cart, turn on the: 'Donation Item' checkbox of this product.
To display the donation amount entry field for all items in the cart, turn on the 'Allow users to give as much as they want, setting their own price for a donation or gift.' cart option.
To display the amount entry field on the product details page got to Module CAT_Products -> 'Attributes' -> 'Text Options / data-entry forms' -> 'Create New' -> Name and Title = 'Donattion Amount '->  Control Type = Amount Entry Field -> Add -> Assign

If you want give your users the ability to select a re-billing period, select: 'User can select period' from the 'Subscription Period / Billing Period' selector of this product and enter the possible re-billing periods into the 'Billing Periods (Every X days). Press ENTER/CR to separate.' textbox of the cart module (select 'View Options' from the module menu)..

pmichael wrote Do we still need to edit the ascx file to hide the "Quantity" label and textfield? Since this is donation for a fund, no point in displaying quantity or ability to alter it from "1"

I see how to freeze it at "1" but I'd prefer not to display Quantity at all.

That's not what I'm seeing in the cart. See if I can give you images here ...

No ... well, I have in the Product config:

Stock is -1       Reorder Point is 0        Selections (orderable quantities) has been -1, 0, 1

Still I always see the "Quantity" label in the cart, even though the number "1" displayed is read-only.

I just want the entire bit to disappear. At this point I have a label "Options" with a value of "Donation Amount" and between that and the Amount label/value is the "Quantity"