hi here is the new fixed PKGBUILD and install file:
the old sane hotplug bug can be closed.

PKGBUILD:
# $Id: PKGBUILD,v 1.17 2004/06/02 10:58:39 eric Exp $
# Maintainer: eric <eric@archlinux.org>
# Contributed by Sarah Hay <sarahhay@mb.sympatico.ca>, Tobias Powalowski <t.powa@gmx.de>

pkgname=sane
pkgver=1.0.14
pkgrel=4
pkgdesc="Scanner Access Now Easy"
depends=('libjpeg' 'libieee1284' 'libusb' 'bash')
source=(ftp://ftp.mostang.com/pub/$pkgname/$pkgname-backends-$pkgver/$pkgname-backends-$pkgver.tar.gz)
url="http://www.sane-project.org"
install=$pkgname.install
backup=(etc/hotplug/usb/libusbscanner etc/hotplug/usb/libsane.usermap)
md5sums=('7ae5bf91aea34ef7956df6f53cf073bd')

build() {
cd $startdir/src/$pkgname-backends-$pkgver
./configure --prefix=/usr --sysconfdir=/etc
/usr/bin/make || return 1
/usr/bin/make DESTDIR=$startdir/pkg install

# install hotplug scripts
/bin/mkdir -p $startdir/pkg/etc/hotplug/usb
/bin/install -m0755 tools/hotplug/libusbscanner \
$startdir/pkg/etc/hotplug/usb/libusbscanner
/bin/install -m0644 tools/hotplug/libsane.usermap \
$startdir/pkg/etc/hotplug/usb/libsane.usermap
}
# vim: ts=2 sw=2 et ft=sh


and sane.install:
# arg 1: the new package version
post_install() {
/bin/cat <<THEEND
NOTE
----
If you use a usb scanner and hotplug than add your user to group 'scanner'
or change the /etc/hotplug/usb/libusbscanner to your needs. If your scanner
is not listed in /etc/hotplug/usb/libsane.usermap add a line for it.

If your usb scanner was turned on before you boot,
you have to unplug and replug it after boot to access it as non root user

or do a sane-find-scanner right after boot
sane-find-scanner which would print "libusb:001:003" for example
Set your permissions with e.g."chmod a+rw /proc/bus/usb/001/003"
in your /etc/rc.local and all should be fine

THEEND
}

# arg 1: the new package version
# arg 2: the old package version
post_upgrade() {
post_install $1
}

# arg 1: the old package version
pre_remove() {
/bin/true
}

# arg 1: the old package version
post_remove() {
/bin/true
}

op=$1
shift
$op $*